Photosensitive epilepsy (PSE) is a physical disorder caused by visual stimuli. The visual stimuli typically includes patterns such as flashing lights and moving objects. These patterns can trigger epileptic seizures. For example, seizures in photosensitive people may be triggered by exposure to television screens due to the flicker or rolling images, to computer monitors, to certain video games or TV broadcasts containing rapid flashes or alternating patterns of different colors, and to intense strobe lights like visual fire alarms.(1) 
People with epilepsy have a 2-14% chance of having seizures precipitated by light or pattern. In the Pokemon cartoon incident in Japan, 685 children visited a hospital in reaction to red-blue flashes on broadcast television(2). Playing video games for extended period of time can cause children to experience many of the same symptoms seen in computer vision syndrome in adults. Extensive viewing of the game screen can lead to eye discomfort, fatigue, blurry vision and headaches. Kids seem to become so addicted to video games that they forget to take breaks. For epileptics even warning not to play video games it will not work.
LUMINANCE is what is measured by a light meter. It's an objective measurement. While BRIGHTNESS however a completely subjective is an attribute of light to which humans assign a label between very dim and very bright. Brightness is perceived, not measured.
The retina does not simply record light intensities. Rather, retinal responses depend on the surrounding context (center-surround receptive field):
1—Photoreceptor cell sensitivity depends on the average/ambient light intensity, due to light adaptation.
2—Retinal ganglion cell responses depend on the difference between light intensity in the center and that in the immediate surrounding.(3) 
Simultaneous brightness contrast and simultaneous color contrast are classical illusions that demonstrate how our perception can be altered by spatial context. Typically, a gray stimulus placed on a bright background appears darker than the same gray stimulus placed on a dark background (e.g., Heinemann, 1955). This phenomenon, called simultaneous brightness contrast, clearly shows the importance of the surrounding luminance in brightness perception.(4) 
High-contrast stimuli are more likely to provoke seizures than are bright lights against a light background.(5) 
The intensity or brightness of the source of light and also the contrast between the light and dark parts during the flicker is also another important factor. If the contrast ratio is greater than 20 candelas/square meter, it poses a risk to the epileptic patients.(6) 
Review of 12 video game programs in 30 subjects suggested that a “steady maximal brightness”>100 lux was a key factor and could (in the presence of other stimuli characteristics) induce seizures in susceptible patients.(7) 
Steady maximal brightness<50 was generally safe. By comparison, steady maximal brightness varied from 6 and 305 lux among video games.(2) 
Both polarized lenses and tinted blue lenses claim to reduce or prevent photosensitive epilepsy by mechanism of anti-glare. Most photosensitive epileptics can prevent the photosensitive reaction by simply covering one eye (monocular vision). Active shutter glasses use the same mechanism to reduce photosensitive epilepsy. Unfortunately the PSE induced not only by glare but in addition by light brightness contrast, fast flashes and even by pattern, etc. In computer video games, the steady maximal brightness could reach 300 lux, and flash frequency could exceed more than 3 Hz which can be a good source to induce PSE caused by high brightness contrast and not because of glare.
It is known in the prior art that a well-lit room is more comfortable and causes less eye-strain when working on a computer screen. One of the recommendations of the Epilepsy Foundation of America, for photosensitive epileptics to keep the room well lit while working on electronic screens in general.(1) The background light will illuminate the peripheral visual field and this will lead to a reduction in contrast between the computer screen and the background light.
The well lit room light intensity is almost 500 lux near the light source, but will decline when it reach the peripheral vision say to 80 lux, while the computer screen light intensity more than 150 lux. Meanwhile the dim room light intensity reaching the eye is almost 10 lux and this is why the well lit room decreases the brightness contrast between peripheral and central vision.